Using "för" to mean "because"

[gokulol]

To be honest, I don't think I've ever heard anyone use "eftersom," but I could be wrong. Is för in this sense more a colloquialism, or is it a dialect thing?

[Arnauti]

Yes, eftersom is the standard usage and för is more colloquial. There's also för att and därför att which can sometimes, but not always, be used in these contexts.

[Zmrzlina]

I hear eftersom from time to time, but as Arnauti says för or därför att is more colloquial.